1. Field of the Invention
This invention relates to a sealing construction used for sealing fluid (vacuum), especially, a sealing construction used for chamber gate portion of a manufacturing apparatus for semiconductors or a surface-processing apparatus for liquid crystal panels.
2. Description of the Related Art
As conventional sealing constructions used for a manufacturing apparatus for semiconductors or a surface-processing apparatus for liquid crystal panels, an O-ring 41 attached to a circular dovetail groove 42 shown in FIG. 9A and a three-leg elastic seal 43 fixed by adhesive to a circular concave groove 44 formed on a metal member 45 shown in FIG. 9B.
However, the O-ring 41 shown in FIG. 9A, having an unstable posture in the dovetail groove 42, may fall out of the dovetail groove 42 and may not show sufficient sealability. And, the elastic seal 43 shown in FIG. 9B requires fixing process with adhesive, and the metal member 45 is difficult to be reused by peeling the elastic seal 43 off the metal member 45 when the elastic seal 43 deteriorates.
To solve the problems above, in a conventional seal construction shown in FIG. 9C, a circular concave groove 44 is formed on an obverse face 46 of a metal member 45, a through hole 49 having an enlarged portion 48 on a reverse face 47 goes through a bottom face of the circular concave groove 44 and the reverse face 47, and a rubber member 50 is unitedly fixed to the through hole 49 and forming a sealing portion 51 in the circular concave groove 44 (refer to Japanese Patent No. 2779946, for example). With this sealing construction, the sealing portion 51 can be kept stable in the circular concave groove 44 without adhesive, and the metal member 45 is reusable.
However, in the conventional seal construction shown in FIG. 9C, a dimple (recess) Z is generated on a surface, corresponding to the part on which the through hole 49 of the sealing portion 51 is disposed, by rubber contraction in cooling process after forming of the rubber member 50, and sealability is spoiled thereby. High pressing force (compression force) does not work on the sealing portion 51 because closing of doors (lids) of a gas storing chamber (a vacuum chamber) of a manufacturing apparatus for semiconductors or a surface-processing apparatus for liquid crystal panels is generally conducted with minimum required pressing force. Therefore, the reduction of sealability by the dimple (recess) is not eliminated.
It is therefore an object of the present invention to provide a sealing construction in which the dimple (recess) is not generated on the part relating to sealability.